Fire protection in concrete demolition, special demolition, interior demolition, as well as in rock excavation and tunnel construction is a safety and organizational principle that shapes all work phases. Wherever load-bearing structures are opened, components separated, materials crushed or tanks cut, ignition sources and fire loads arise and, in the event of an incident, smoke and heat are released. An effective fire protection concept combines technical, structural and organizational measures. In practice, the selection of cutting and crushing methods, the handling of hydraulic power packs and the control of sparks, heat and dust play a central role. In particular, low-spark hydraulic methods, such as using concrete pulverizers or hydraulic rock and concrete splitters, can reduce fire risks under certain boundary conditions without impairing work objectives.
Definition: What is meant by fire protection
Fire protection refers to the totality of all measures that prevent the origin and spread of fires, protect people and property, and support the deployment capabilities of the fire brigade. It is typically divided into structural, systems-based and organizational fire protection as well as defensive fire protection. Objectives include, among others, limiting fire loads, ensuring sufficient fire resistance durations, guaranteeing functional escape routes, effective fire and smoke compartments, and the provision of suitable extinguishing agents. In deconstruction and tunnel projects, temporary protective measures are additionally used to maintain the safety level during construction states.
Protection objectives and levels of fire protection in deconstruction and tunnel construction
In existing buildings, industrial facilities and underground, fire protection addresses three core objectives: protection of life and health, protection of assets and infrastructure, and safeguarding operational and construction-sequence continuity. These goals are achieved through coordinated levels: structural separations and fire stops, systems-based installations such as fire detection and extinguishing systems (if in operation), as well as work organization, instruction and supervision. Deconstruction phases alter fire compartments, routing of services and ventilation flows—therefore temporary adjustments are essential, such as mobile fire stops, keep-clear zones, modified escape routes and the specification of low-spark methods in sensitive areas.
Structural fire protection in existing buildings
Fire resistance classes, fire walls, fire stopping of penetrations and fire-protected corridors quickly lose their original function during deconstruction. Sawing, drilling and cutting open components create new fire and smoke paths. Forward-looking sequencing—open, cut, temporarily close—and verification of residual load-bearing capacity and fire compartment boundaries after each phase are crucial to prevent uncontrolled smoke spread.
Organizational fire protection on construction sites
Clear rules apply to interior demolition and cutting: keep access and escape routes clear, minimize fire loads, control ignition sources, provide extinguishing agents, schedule a fire watch and allow hot work only under controlled conditions. Documented permits, clear on-site responsibility and communication chains ensure responsiveness if heating, smoldering or smoke occurs.
Fire hazards during demolition, cutting and severing work
Deconstruction and cutting processes generate ignition sources and energies to varying degrees. Relevant hazards arise from flying sparks, hot surfaces, frictional heat, electrical defects, combustible dusts and vapors, as well as concealed residual media in lines, tanks or cavities.
- Sparks and glowing particles during thermal cutting and grinding
- Heating and ignition sources at drives, hydraulic hose lines and power units
- Combustion-promoting deposits: dust, fibers, bitumen, old coatings
- Explosive atmosphere in vessels, ducts or enclosed areas
- Smoke and heat build-up in shafts, basements or tunnel tubes
Low-spark methods versus spark-generating methods
Where fire protection has priority—such as in interior demolition of active building areas, sensitive production environments or tunnel construction—hydraulic cutting and crushing methods offer advantages: concrete pulverizers crush concrete in a controlled manner and reduce spark formation compared to thermal methods. Rock and concrete splitters develop high splitting pressure in the borehole and produce neither flame nor sparks. This supports protection against fire and smoke development, especially in areas with limited ventilation or elevated fire load. Nevertheless, smoldering due to friction on dry material and heated particles cannot be ruled out—follow-up inspections remain necessary.
Hydraulic power packs and energy supply
Hydraulic power units supply shears and split cylinders with energy. From a fire protection perspective, leakage prevention, safe storage of fuels, suitable containment systems and the removal of ignition sources in the immediate vicinity are central. Lines must be routed to protect them from mechanical damage; emergency stop devices must be accessible and clearly marked. Regular monitoring of operating temperatures and a clean work area prevent combustible dusts from adhering to hot surfaces.
Tool and method selection from a fire protection perspective
The choice of equipment significantly influences fire risk. Depending on the construction task, material, ambient air change and proximity to fire loads, it must be weighed whether mechanical cutting, hydraulic crushing or thermal methods are used. In many scenarios with heightened fire protection requirements, low-spark, low-vibration and reduced-emission methods are advantageous, provided they meet the structural objectives.
Concrete pulverizers in interior demolition and special demolition
Concrete pulverizers crush reinforced concrete components without an open flame. Heat generation remains limited compared to hot work, and spark formation is generally low. In interior demolition of active building areas, temporary fire compartments can be observed more reliably; at the same time, controlled removal facilitates securing escape routes. For cutting massive reinforcing steel, steel shears or multi cutters can be used in addition.
Rock and concrete splitters in tunnel construction and rock excavation
Rock and concrete splitters as well as rock splitting cylinders operate without explosives. They transmit controlled forces into the borehole and reduce ignition sources, which can be an advantage in tunnels and galleries with limited air exchange. Lower spark and heat generation counteracts the risk of concealed smoldering fires; at the same time, visibility for spatially constrained rescue routes is maintained longer due to reduced smoke.
Tank cutters and work on vessels
When cutting tanks or piping, explosion protection and fire prevention take precedence. Methods that work without an open flame can reduce ignition hazards. Fundamental measures include verified absence of media, sufficient ventilation or inerting of the vessel atmosphere, and continuous measurements. Extinguishing agents and isolation concepts must be provided before starting; follow-up inspections include the risk of smoldering in insulation or deposits.
Combination shears, multi cutters and steel shears
Hydraulic shears cut metal without a flame. Compared to thermal methods, fewer hot particles usually occur; nevertheless, shielding and control of stray sparks are required, especially in areas with combustible coatings, cable bundles or dust accumulations. A careful sequence—secure first, then cut—prevents uncontrolled movement and friction that could create additional heat sources.
Planning and interfaces with the fire protection concept
Deconstruction changes the effectiveness of existing fire protection measures. Close coordination with the overarching fire protection concept and with operational processes is required, for example when temporarily deactivating detection devices, adapting escape routes or using ventilation underground. Documented action plans, defined escalation paths and specifying low-spark methods in particularly exposed zones increase resilience.
Temporary fire compartments and fire stops
Provisional fire stops, mobile fire curtains or closable openings limit smoke spread. Penetrations for lines and hoses must be routed so that the fire seal is maintained; unused openings are closed. Transitions between construction states are accompanied by clear inspection and acceptance processes.
Extinguishing agents, water and foam management
Type, quantity and location of extinguishing agents depend on the materials, geometry and accessibility of the worksite. In tunnel tubes, reach and accessibility take priority; in buildings, proximity to escape routes. Firefighting water retention and protection against contamination-related environmental damage must be considered. Water mist can limit smoke and heat layers; powder extinguishers and CO2 extinguishers are to be selected with regard to material compatibility and visibility conditions.
Construction site organization: measures for daily operations
Fire protection is implemented on the construction site every day. A clear, repeated routine minimizes errors and increases safety in all areas—from concrete demolition through interior demolition to tunnel construction.
- Update the hazard analysis regularly; mark zones with elevated fire load.
- Select methods with an eye to sparks, heat, dust and smoke—prefer low-spark methods where feasible.
- Allow hot work only with documented permit; schedule a fire watch and follow-up inspection.
- Clearly mark and keep clear extinguishing agents, emergency stop, escape routes and assembly points.
- Set up hydraulic power packs safely, avoid leaks, store media in an orderly manner.
- Prevent accumulations of dust and chips; clean work areas regularly.
- Check electrical installations and the construction power supply; protect cable runs from damage.
- Store gas cylinders, fuels and oils separately, ventilated and secured against tipping over.
- Ensure communication: responsibilities, alarm procedures and location information available at all times.
- Monitor follow-up work and cooling phases before areas are released.
Material behavior: concrete, steel and natural stone under fire exposure
Concrete can be prone to spalling at high temperatures; load-bearing capacity decreases as reinforcing steel loses strength. Steel heats up faster and loses load-bearing capacity at high temperatures; natural stone behaves differently depending on its structure. For planning demolition sequences, it is important to keep heat input low and to avoid uncontrolled heating of components—another reason to consider low-spark and thermally restrained methods.
Smoke and visibility in tunnels
In tunnels and galleries, smoke management and ventilation are critical. Methods with low smoke and dust generation preserve visibility, support orientation and facilitate rescue. Coordinated ventilation flows prevent the accumulation of hot gases and remove dust—care must be taken that airflow does not drive sparks into endangered zones.
Documentation, training and communication
Training on ignition sources, extinguishing agents, escape routes and emergency stop must be repeated regularly. Teams must know the particularities of concrete pulverizers, rock and concrete splitters, steel shears, multi cutters, combination shears and tank cutters—especially regarding functional limits, energy supply and possible ignition sources. Complete documentation of permits, inspections and acceptances creates transparency and traceability.
Environmental protection in the context of fire protection
Fire protection and environmental protection go hand in hand: firefighting water retention, handling of contaminated residues and the protection of soil and water must be considered. Methods that work without an open flame and generate less smoke and soot can reduce the risk of secondary damage. A clean, orderly construction site reduces fire loads and facilitates control of potential ignition sources.